The tray only knew what this browser had scheduled (localStorage), but
Synapse lists every pending one via MSC4140 GET /delayed_events. Load it
when the tray mounts and on window focus (localStorage stays as a first-
paint cache), keeping only non-state m.room.message events. Logout now
says "N scheduled messages still send after you log out" and offers to
cancel them.
Fixes#322
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5